<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<script>
		// 函数的重写  js 允许函数重写，php是不允许
		// 
		var name = "学并思";
		function alert(str1,str2) {
			var name = "xbs";
			var num = 2000;
			document.write(name);
		}

		alert(10,20);

		document.write(name);




	</script>
</head>
<body>
	
</body>
</html>